1. Field of Invention
This invention relates to the process for coupling polyester materials. Coupling polyesters includes preparing extended chain polyesters, and graft or block polyesters and copolyesters. Coupling as described above is referred to herein as a chain extension process. Improved extended chain polyesters, and block or graft copolyesters of this invention lack discoloration attributes of many materials of the prior art. Extended chain polyesters, and block or graft polyesters and copolyesters prepared in accordance with the process of this invention are capable of being fabricated into useful shaped articles of manufacture, e.g. filaments, both mono- and multifilament, films, tapes, ribbons, rods, laminates and the like.
2. Description of the Prior Art
U.S. Pat. No. 4,568,720 to Aharoni discloses a process for preparing extended chain polyesters, and block or graft polyester or copolyesters by forming an intimate mixture of one or more polyesters and an effective amount of one or more chain extension reagent compounds, and thereafter heating the intimate mixture at a temperature and for a time sufficient to form the desired amount of the desired polyester or copolyester.